Choose a thick fabric
Since the meticulous construction of a tailor-made piece will make it last a life time, it's important that the fabric has longevity. While a super 150s suit might feel amazingly light, it will wear pretty quickly. If you can't afford to splash out on a number of bespoke pieces to replace one after the other, you're better off going for a somewhat thicker, more durable fabric. British made Worsted wools are ideal.